Assessment of Antitheilerial Activity of the Aqueous Extract of Kigelia africana Unripe Fruits against Theileria lestoquardi

Aims: To investigate the in vitro schizonticidal activity of aqueous extract of Kigelia africana unripe fruits (Um shotour) Lam. Benth. In Hook. against Theileria lestoquardi.

Study Design: In vitro screening of the aqueous extract of the fruits at different concentrations against T. lestoquardi.

Place and Duration of Study: University of Khartoum, Veterinary Research Institute, Medicinal and Aromatic Plants Research Institute, Khartoum, Sudan, between September 2007 and August 2009.

Methodology: Aqueous extract of K. africana fruits was screened for the first time to test in vitro activity against T. lestoquardi at different concentrations. Blood was collected separately from normal sheep and sheep infected naturally with T. lestoquardi. Normal Lymphocyte cells and lymphocyte cells infected with T. lestoquardi were isolated from heparinized blood with Ficoll-paque, grown in minimum essential medium and sub cultured continuously till passage 8 (5x104 cell/ml) which was used for the test. The parasite was identified with indirect fluorescent antibody test.

Results: The results revealed in vitro activities of 20%, 58% and 80% at concentrations of 500, 5000 and 10000 µg/ ml, respectively. Lethal dose 50% (LC50) was 2660.28 µg/ ml. The extract activity significantly (P<0.05) caused death of macroschizonts, decreasing the number of macroschizonts per cell, and significantly (P<0.05) increasing the number of extra cellular macroschizonts at concentrations of 5000 and 10000 µg/ml. The number of dividing cells, and number of viable cells significantly (P<0.05) decreased at concentrations of 5000 and 10000 µg/ml compared with the control. Beside the activity, the highest concentration 10000 µg/ml revealed some lymphoblast cells with vacuolated cytoplasm.

Conclusion: This study showed that aqueous extract of K. africana fruits has antitheilerial effect on T. lestoquardi and could be an effective candidate for the treatment of malignant ovine theileriosis after in vivo confirmation. Further studies are recommended for phytochemical analysis and mode of action.